Disconnecting contact



Nov. 14, 1961 E. c. GOODWIN, JR., ETAL DISCONNECTING CONTACT 2Sheets-Sheet 1 Filed Aug. 27, 1959 (Momma plww J2. swam/14m.

27M fol/MAM W 5.

@MZQW Nov. 14, 1961 E. c. csoonwm, JR., ETAL 3,009,043

DISCONNECTING CONTACT 2 Sheets-Sheet 2 Filed Aug. 27, 1959 UM/0mm50140144 Edp dwM4,JA.

31km fake/{00M y WM 5 aw/K442 Jnsl rates This invention relates toelectric circuit interrupters and more particularly to a new andimproved arrangement for primary disconnect contacts wherein each of aplurality of finger contacts is guided and retained within a housing.

In electrical circuit interrupting devices such as high voltage circuitbreakers it is necessary to provide primary disconnect contacts so thatthe circuit breaker can be selectively connected and disconnected fromthe electrical circuit it protects. Heretofore primary disconnectcontacts have been used employing a plurality of finger contactsdesigned and constructed so that each finger contact may be individuallybiased by coil springs arranged within a housing. This housing merelyserves as an enclosure. It is not flexible enough to compensate formisalignment of the breaker and its cubicle while providing uniformspacing for the contact fingers and springs. The prior art structuresare costly to manufacture and require expensive tools to assemble anddisassemble in the field.

In accordance with the invention claimed a new and improved primarydisconnect contact is provided which employs an interleavedsubstantial-1y dustproof enclosure which is flexible enough tocompensate for misalignment of the circuit breaker and its cubicle. Thedisconnect contact structure is completely self-contained having noloose parts and the biasing springs located at each end of the contactfingers serve the dual purpose of providing contact finger pressure andthe force which locks the parts of the assembly together. The new andimproved contact structure provides uniform spacing for the contactfingers and springs, and improved conduction and radiation surfaces arearranged in intimate contact with the side walls of the current carryingfinger contacts.

It is, therefore, an object of this invention to provide a new andimproved primary disconnect contact structure.

Another object of this invention is to provide 'a new and improvedprimary disconnect contact in which a housing serves as a positioning,pivoting and retaining means for a plurality of finger contacts.

A further object of this invention is to provide a new and improvedprimary disconnect contact in which the housing comprising a pluralityof interleaved parts is locked together by the contact biasing means.

A still further object of this invention is to provide a housing for aplurality of finger contacts employing improved conduction and radiationsurfaces in intimate contact wtih the side walls of the finger contacts.

Objects and advantages other than those set forth will be apparent fromthe following description when read in connection with the accompanyingdrawing, in which:

FIG. 1 is an isometric view with parts broken away of a primarydisconnect contact embodying the present invention;

FIG. 2 is a left end view of the structure shown in FIG. 1 with partsbroken away;

FIG. 3 is 'a cross sectional view of the structure shown in FIG. 2 takenalong the line IlIlII;

FIG. 4 is an elevational view of one of the spacer members forming theinterleaved housing structure shown in FIGS. 1-3;

FIG. 5 is a plan view illustrating the manner in which two adjacentspacer members interlock together;

FIG. 6 is a cross sectional view illustrating the invenatent "are actersof reference, FIGS. 1, 2 and 3 illustrate an electric.

switch and more particularly a primary disconnect contact 10 for acircuit breaker structure. Contact 10 is attached to an electricconductor or stud 11 usually forming a part of a circuit breaker. Theprimary disconnect contact 10 comprises a plurality of finger typecontacts 12 which are spacedly mounted around stud 11 for independentlimited movement in a housing 15. Housing 15 comprises a first ringshaped member 13 and a second ring shaped member 14 with member 14 beingmounted at least partly around stud 11 and in spaced relationship withmember 13. Members 13 and 14 are pivo-tally interconnected by aplurality of interleaved spacer members 16 which are arranged to extendsubstantially longitudinally of stud 11.

Each of the ring shaped members 13 and 14 is provided with a firstarcuate surface 17 extending around its periphery with surface 17 facingthe center of the ring, and a flange 18 extending inwardly of surface 17providing a second arcuate surface 19 spaced from and facing surface'17.

Each of the spacer members 16 may have, for example, a tr-oughlike shape26 having flanges 21 and 22 extending therefrom (as shown in FIGS. 4 and5) along its longitudinal edges. Flange 21 is provided with arcuateprojections 23 which fit into a continuous annular recess 24 extendingaround the circumference of each of the ring shaped members 13 and 14.Projections 23 of spacer members 16 are loosely arranged or pivotallymounted in recess 24 in ring shaped members 13 and 14 for providinglimited lateral movement of these ring members relative to each other.When spacer members 16 are arranged around ring shaped members 13 and 14to form the unitary housing 15, flange 22 of one spacer member overlapsflange 21 of an adjacent spacer member so that an interleaved structureis created interconnecting ring shaped members 13 and 14. The troughs 20of spacer members 16 project inwardly of ring shaped members 13 and 14(as shown in FIG. 1) to form a plurality of cooling cavities extendinglongitudinally of housing '15 and stud 11. By interleaving spacermembers 16, as shown, a predetermined space is provided between adjacentspacer members which space is partially enclosed by the walls formingtroughs 2t 1 Finger contacts 12 are each mounted to extend withinflanges 18 of ring shaped members 13 and 14. A pair of spring biasingmeans such as coil springs are arranged one at each end of fingercontacts 12 within flanges 18 of each ring shaped member and within thespace between adjacent troughs 2t). Finger contacts 12 are provided ateach end thereof with a flat surface 27, and coil springs 26 are eacharranged between a surface 27 and a flange 22. These coil springs biasthe finger contacts 12 radially inward toward the center of the assemblyagainst the arcuate surfaces 19 of flange 18. Each of the fingercontacts 12 is provided with a pair of spaced contact engaging surfaces28 and 29 one of which is arranged to engage stud 11 and the other ofwhich is arranged to engage a movable contact stud 30 shown in FIG. 6.In order to firmly attach the disconnect contact structure 19 to stud 11finger contacts 12 are each provided with a groove 32 into which theouter periphery 33 of ring shaped yoke 34 is arranged to extend. Yoke 34is threadedly attached to the terminal end of stud 11 by means 3 ofbolts 35 spacedly arranged around the periphery of yoke -34.

Since electrical engagement between finger contacts 12 and stud 11 willmove contacts 12 radially outward against the bias of coil springs 26mounted in ring shaped member 14, the arcuate surface 19 of ring shapedmember 13 controls the movement of contacts 12. Finger contacts 12 pivotaround their contact surfaces 28 and around the outer edge of yoke 34-arranged in groove 32. Surface 19 of ring shaped member 14 controls themovement of finger contacts 12 when stud 30 is forced between thecontact surf-aces 29 of finger contacts 12.

The greater the force of the spring biasing means 26 for each fingercontact the greater will be the entering force required for electricalengagement between the primary disconnect contact assembly 16 and stud30.

As noted from FIG. 2 of the drawing, housing 15 comprises a plurality ofinterleaved spacer members 16 which provide spring openings therebetweenevenly spaced around the inside of the periphery of ring shaped members13 and 14. Into these openings are arranged coil springs 26 which notonly bias the finger contacts toward the longitudinal axis of thehousing but bind the primary disconnect contact structure into a unitarydevice. The finger contacts 12 comprise substantially fiat conductingmembers having their contact surfaces '28 and 29 spaced from each otherat different ends thereof on difierent sides of groove 32. The peripheryof yoke 34 loosely fits into groove 32 and the conducting surfaces 28are brought into high pressure electrical contact with stud 11 when theprimary disconnect contact 16 is assembled on stud 11. When the primaryconductor stud 30 is moved into engagement with the primary disconnectcontact coil springs 26 in ring shaped member 13 bias the contactsurfaces 29 of finger contacts 12 into high pressure electricalengagement with primary conductor stud '30. Finger contacts 12 areindividually movable and each are pivotally mounted about either of itssurfaces 28 or 29 depending on the alignment of studs 11 and 313'. Eachfinger contact is provided with its individual biasing means such ascoil springs 26 to bias it into high pressure electrical engagement withthe contact studs 11 and 30. Thus, in the event any one of the pluralityof coil springs should fail there will be sufiicient force from theremaining coil springs on other finger contacts 12 to maintain highpressure electrical engagement. Since each coil spring 26 maintains itsindividual finger contact 12 in high pressure contact with studs 11 and30 loss of any one spring merely causes loss of only one point of highpressure contact.

It is further noted that when stud 31 is removed from the primarydisconnect contact 14 the coil springs 26 arranged within ring shapedmember 13 combine with the arcuate surface 19 of flange 18 to maintainfinger contacts 12 in their given circular configuration. The inner rimof the ring shaped members 13- and 14 and particularly their arcuatesurfaces 19 act as stops to limit the positions of the finger contacts12 in the stud disengaged positions. Thus limited, the force required toinitiate contact engagement is held to a minimum. This condition alsoprovides the required electrical clearance in the test position of thecircuit breaker using this disconnect contact structure with a minimumof breaker withdrawal motion.

In view of the fact that rings 13 and 14 are flexibly supported by theinterleaved spacer members 16 in alateral plane independently of eachother, they provide outer support for the finger contacts and therebymaintain continuous equalized pressure of each individual finger contactwithin the prescribed limits of misalignment of the circuit breaker andits associated contact studs. These limits are defined by the engagementclearances between the mounting plate or yoke 34 and the slots orgrooves 32 in the finger contacts 16 with which yoke 34 mates. Theleading edge 37 of flange 18 of ring shaped member 13 may also becontoured to readily engage cubicle stud 30 and flexibly align theprimary disconnect contact 11) therewith to assure substantiallyconcentric engagement of the stud with the finger contact assembly.

As readily noted from the drawing the primary disconnect contact whencompletely assembled provides relatively large surface areas fordissipation of heat. In order to further increase the heat dissipationof the contact, assembly flanges 18 of ring shaped members 13 and 14 areeach provided with a plurality of apertures or slots 38 which incombination with the spaces between the finger contacts 12 providesventing passageways through the primary disconnect contactlongitudinally thereof.

These passageways provide additional heat dissipation by convection.

FIGS. 7 and 8 illustrate a modification of the structure shown in FIGS.1-6 wherein the annular ring shaped members 13 and 14 are provided witha plurality of indentations 39 spaced around their circumferences inplace of the continuous annular recess 24 shown in FIGS. 1, 2 and 3.indentations 39 form pockets for loosely receiving projections 23 ofspacer members 16 thereby providing pivotal connections of spacermembers 16 to ring shaped members 13 and 14. indentations 39 also form agiven position for the mounting of spacer members 16 around ring shapedmembers 13 and 14 and assures a given space between each of the spacermembers.

Although but two embodiments of the present invention have beenillustrated and described, it will be apparent to those skilled in theart that various changes and modifications may be made therein withoutdeparting from the spirit of invention or from the scope of the appendedclaims.

What is claimed is:

1. A contact structure for a circuit breaker stud comprising a pluralityof contacts, means for mounting said contacts around said stud forindependent limited movement, said means comprising a pair of spacedmembers one at least partly surrounding said stud and spacer members forpivotally interconnecting said spaced members for limited lateralmovement of said spaced members, each of said spaced members having afirst surface extending substantially longitudinally of said stud and aflange extending inwardly of said first surface, said flange providing asecond surface spaced from and facing said first surface, said contactseach being mounted to extend with-in said flange of each of said spacedmembers, and a plurality of spring biasing means one arranged at eachend of said contacts within said flange of each of said spaced membersand between said first surfaces and said contacts, said biasing meansbiasing the ends of said contacts toward said second surface of saidspaced members, at least a part of said contacts engaging said stud whensaid stud is inserted within one of said spaced members.

2. A contact structure for a circuit breaker stud comprising a pluralityof finger contacts, means for mounting said finger contacts around saidstud for independent limited movement, said means comprising a pair ofarcuate spaced members one at least partly surrounding said stud andspacer members for pivotall-y interconnecting said spaced members, eachof said spaced members having a first surface extending substantiallylongitudinally of said stud and a flange extending inwardly of saidfirst surface, said flange providing a second surface spaced from andfacing said first surface, said finger contacts each being mounted toextend within said flange of each of said spaced members, and aplurality of spring biasing means one arranged at each end of saidfinger contacts within said flange of each of said spaced members andbetween said first surfaces and said finger contacts, said biasing meansbiasing the ends of said finger contacts toward said second surface ofsaid spaced members, said finger contacts each being provided with apair of spaced contact engaging surfaces, one of said surfaces of eachof said finger contacts engaging said stud when said stud is insertedwithin one of said spaced members.

3. A contact structure for a circuit breaker stud comprising a pluralityof finger contacts, means for mounting said finger contacts on said studfor indepedent limited movement, said means comprising a first ringshaped member, a second ring shaped member and spacer members forpivotally interconnecting said first and second ring shaped members forlimited lateral movement, each of said ring shaped members having afirst surface extending substantially longitudinally of said stud and aflange extending inwardly of said first surface, said flange providing asecond surface spaced from and facing said first surface, said fingercontacts each being mounted to extend within said flange of each of saidring shaped members, and a plurality of spring biasing means onearranged at each end of said finger contacts within said flange of eachof said ring shaped members and between said first surfaces and saidfinger contacts, said biasing means biasing the ends of said fingercontacts toward said second surface of said ring shaped members, saidfinger contacts each being provided with a pair of spaced co-ntactengaging surfaces, one of said surfaces of each of said finger contactsengaging said stud when said stud is inserted within one of said ringshaped members.

4. A contact structure for a circuit breaker stud comprising a pluralityof finger contacts, means for mounting said finger contacts on said studfor independent limited movement, said means comprising a first ringshaped member, a second ring shaped member and spacer members forpivotally interconnecting said first and second ring shaped members forlimited lateral movement of said ring shaped members, each of said ringshaped members having a first surface extending substantiallyiongitudinally of said stud and a flange extending inwardly of saidfirst surface, said flange providing a second surface spaced from andfacing said first surface, said finger contacts each being mounted toextend Within said flange of each of said ring shaped members, and aplurality of spring biasing means one arranged at each end of saidfinger contacts within said flange of each of said ring shaped membersand between said spacer members and said finger contacts, said biasingmeans biasing the ends of said finger contacts toward said secondsurface of said ring shaped members, said finger contacts each beingprovided with a pair of spaced contact engaging surfaces, one of saidsurfaces of each of said finger contacts engaging said stuid when saidstud is inserted within one of said ring shaped members.

5. A contact structure for a circuit breaker stud comprising a pluralityof finger contacts, means for mounting said finger contacts on said studfor independent limited movement, said means comprising a first ringshaped member, a second ring shaped member and spacer members forinterconnecting said first and second ring shaped members, each of saidring shaped members having a first surface extending substantiallylongitudinally of said stud and a flange extending inwardly of saidfirst surface, said flange providing a second surface spaced from andfacing said first surface, each of said spacer members being pivotallyconnected at different ends thereof to said first surface of differentones of said ring shaped members for providing limited lateral movementof said ring shaped members, said finger contacts each being mounted toextend within said flange of each of said ring shaped members, aplurality of spring biasing means one arranged at each end of saidfinger contacts within said flange of each of said ring shaped membersand between said spacer members and said finger contacts, said meansbiasing the ends of said finger contacts toward said second surface ofsaid ring shaped members, said finger contacts each being provided witha pair of spaced contact engaging surfaces, one of said surfaces of eachof said finger contacts engaging said stud when said stud is insertedwithin one of said ring shaped members.

6. A contact structure for a circuit breaker stud comprising a pluralityof finger contacts, means for mounting surface extending substantiallylongitudinally of said stud and a flange extending inwardly of saidfirst surface, said flange providing a second surface spaced from andfacing said first surface, each of said spacer members being pivotallyconnected at different ends thereof to said first surface of differentones of said ring shaped members for providing limited lateral movementof said ring shaped members, said finger contacts each being mounted toextend Within said flange of each of said ring shaped members, aplurality of spring biasing means'one arranged at each end of saidfinger contacts within said flange of each of said ring shaped membersand between said spacer members and said finger contacts, said biasingmeans biasing the ends of said finger contacts toward said secondsurface of said ring shaped members, said finger contacts each beingprovided with a pair of spaced contact engaging surfaces, a groovearranged within each of said finger contacts between said contactengaging surfaces, and a ring shaped yoke arranged to extend within saidgrooves of each of said finger contacts for mounting said structure toan end of said stud.

7. A contact structure for a circuit breaker stud comprising a pluralityof finger contacts, means for mounting said finger contacts on said studfor independent limited movement, said means comprising a first ringshaped member, a second rin-g shaped member and spacer members forinterconnecting said first and second ring shaped members, each of saidring shaped members having a first arcuate surface extending around itsperiphery with said first surface facing the center of said ring shapedmember and a flange extending inwardly of saidfirst surface, said flangeproviding a second arcuate surface spaced from and facing said firstsurface, each of said first surfaces being provided with a plurality ofspaced indentations extending around its circumference, each of saidspacer members being provided with a protrusion at each end thereof forconnecting with said indentations of said first surface of differentones of said ring shaped members for providing limited lateral movementof said ring shaped members, said finger contacts each being mounted toextend within said flange of each of said ring shaped members, aplurality of spring biasing means one arranged at each end of saidfinger contacts within said flange of each of said ring shaped membersand between said spacer members and said finger contacts, said meansbiasing the ends of said finger contacts to- Ward said second surface ofsaid ring shaped members and said protrusions into said indentations,said finger contacts each being provided with a pair of spaced contactengaging surfaces, one of said surfaces of each of said finger contactsengaging said stud when said stud is inserted within one of said ringshaped members.

8. A contact structure for a circuit breaker stud comprising a pluralityof finger contacts, means for mounting said finger contacts on said studfor independent limited movement, said means comprising a first ringshaped member, a second ring shaped member and spacer members forinterconnecting said first and second ring shaped members, each of saidring shaped members having a first arcuate surface extending around itsperiphery with said first surface facing the center of said ring shapedmember and a flange extending inwardly of said first surface, saidflange providing a second arcuate surface spaced from and facing saidfirst surface, each of said first surfaces being provided with aplurality of spaced indentations extending around its circumference,each of escapes said spacer members being provided with a protrusion ateach end thereof for pivotally connecting with said indentation of saidfirst surface of different ones of said ring shaped members forproviding limited lateral movement of said ring shaped members, saidfinger contacts each being mounted to extend within said flange of eachof said ring shaped members, a plurality of spring biasing means onearranged at each end of said finger contacts within said flange of eachof said ring shaped members and between said spacer members and saidfinger contacts, said means biasing the ends of said finger contactstoward said second surface of said ring shaped members and saidprotrusions into said indentations, said finger contacts being providedwith a pair of spaced contact engaging surfaces, a groove arrangedwithin each of said finger contacts between said contact engagingsurfaces, and a ring shaped yoke arranged to extend within said groovesof each of said finger contacts for mountnig said structure to an end ofsaid stud.

9. A contact structure for a circuit breaker stud comprising a pluralityof finger contacts, means for mounting said finger contacts on said studfor independent limited movement, said means comprising a first ringshaped member, a second ring shaped member and parallelly arrangedspacer members for interconnecting said first and second ring shapedmembers, each of said ring shaped members having a first arcuate surfaceextending around its periphery with said first surface facing the centerof said ring shaped member and a flange providing a second arcuatesurface spaced from and facing said first surface, each of said firstsurfaces being provided with a plurality of indentations equally spacedaround its circumference, each of said spacer members being providedwith a protrusion at each end thereof pivotally connected with saidindentation of said first surface of different ones of said ring shapedmembers for providing limited lateral movement of said ring shapedmembers, said finger contacts each being mounted to extend Within saidflange of each of said ring shaped members, a plurality of springbiasing means one arranged at each end of said finger contacts withinsaid flange of each of said ring shaped members and between said spacermembers and said finger contacts, said means biasing the ends of saidfinger contacts toward said second surface of said ring shaped membersand said protrusions into said indentations, said finger contacts eachbeing provided with a pair of spaced contact engaging surfaces, a groovearranged within each of said finger contacts between said contactengaging surfaces, and a ring shaped yoke arranged to extend within saidgrooves of each of said finger contacts for mounting said structure toan end of said stud.

10. A contact structure for a circuit breaker stud comprising aplurality of finger contacts, means for mounting said finger contacts onsaid stud for independent limited movement, said means comprising afirst ring shaped member, a second ring shaped member and interleavedspacer members for interconnecting said first and second ring shapedmembers, each of said ring shaped members having a first arcuate surfaceextending around its periphery with said first surface facing the centerof said ring shaped member and a flange extending inwardly of said firstsurface, said flange providing a second arcuate surface spaced from andfacing said first surface, each of said spacer members being pivotallyconnected at different ends thereof to said first surface of differentones of said ring shaped members for providing limited lateral movementof said ring shaped members, each of said spacer members being formed toprovide a trough extending longitudinally of said spacer member inwardlyof said ring shaped members and a pair of flanges one on each side ofand extending along said trough, said flanges of said spacer membersoverlapping to provide a space between adjacent troughs, said fingercontacts each being mounted to extend wit-bin said flange of each ofsaid ring shaped members, a plurality of spring biasing means onearranged at each end of said finger contacts between adjacent troughsand within said flange of each of said ring shaped members and betweensaid flanges of said spacer members and said finger contacts, saidfinger contacts each being provided with a pair of spaced contactengaging surfaces, a groove arranged within each of said finger contactsbetween said contact engaging surfaces, and a ring shaped yoke arrangedto extend Within said grooves of each of said finger contacts formounting said structure to an end of said stud.

11. Avcontact structure for a circuit breaker stud comprising aplurality of finger contacts, means for mounting said finger contacts onsaid stud for independent limited movement, said means comprising afirst ring shaped member, a second ring shaped member and spacer membersfor interconnecting said first and second ring shaped members, each ofsaid ring shaped members having a first arcuate surface extending aroundits periphery with said first surface facing the center of said ringshaped member and a flange extending inwardly of said first surface,said flange providing a second arcuate surface spaced from and facingsaid first surface, each of said first surfaces being provided with anannular recess extending around its circumference, each of said spacermembers being provided with a protrusion at each end thereof forconnecting with said recess of said first surface of different ones ofsaid ring shaped members for providing limited lateral movement of saidring shaped members, said finger contacts each being mounted to extendwithin said flange of each of said ring shaped members, a plurality ofspring biasing means one arranged at each end of said finger contactswithin said flange of each of said ring shaped members and between saidspacer members and said finger contacts, said means biasing the ends ofsaid finger contacts toward said second surface of said ring shapedmembers and said protrusions into said recesses, said finger contactseach being provided with a pair of spaced contact engaging surfaces, oneof said surfaces of each of said finger contacts engaging said stud whensaid stud is inserted within one of said ring shaped members.

12. A contact structure for a circuit breaker stud comprising aplurality of finger contacts, means for mounting said finger contacts onsaid stud for independent limited movement, said means comprising afirst ring shaped member, a second ring shaped member and spacer membersfor interconnecting said first and second ring shaped members, each ofsaid ring shaped members having a first arcuate surface extending aroundits periphery with said first surface facing the center of said ringshaped member and a flange extending inwardly of said first surface,said flange providing a second arcuate surface spaced from and facingsaid first surface, each of said first surfaces being provided with anannular recess extending around its circumference, each of said spacermembers being provided with a protrusion at each end thereof forpivotally connecting with said recess of said first surface of differentones of said ring shaped members for providing limited lateral movementof said ring shaped members, said finger contacts each being mounted toextend within said flange of each of said ring shaped members, aplurality of spring biasing means one arranged at each end of saidfinger contacts within said flange of each of said ring shaped membersand between said spacer members and said finger contacts, said meansbiasing the ends of said finger contacts toward said second surface ofsaid ring shaped members and said protrusions into said recesses, saidfinger contacts being provided with a pair of spaced contact engagingsurfaces, a groove arranged within each of said finger contacts betweensaid contact engaging surfaces, and a ring shaped yoke arranged toextend within said grooves of each of said finger contacts for mountingsaid structure to an end of said stud.

13. A contact structure for a circuit breaker stud comprising aplurality of finger contacts, means for mounting said finger contacts onsaid stud for independent limited movement, said means comprising afirst ring shaped member, a second ring shaped member and parallellyarranged spacer members for interconnecting said first and second ringshaped members, each of said ring shaped members having a first arcua-tesurface extending around its periphery with said first surface facingthe center of said ring shaped member and a flange providing a secondarcuate surface spaced from and facing said first surface, each of saidfirst surfaces being provided with an annular recess spaced around itscircumference, each of said spacer members being provided with aprotrusion at each end thereof pivotally connected with said recess ofsaid first surface of different ones of said ring shaped members forproviding limited lateral movement of said ring shaped members, saidfinger contacts each being mounted to extend within said flange of eachof said ring shaped members, a plurality of spring biasing means onearranged at each end of said finger contacts within said flange of eachof said ring shaped members and between said spacer members and saidfinger contacts, said biasing means biasing the ends of said fingercontacts toward said second surface of said ring shaped members and saidprotrusions into said recesses, said finger contacts each being providedwith a pair of spaced contact engage surfaces, a groove arranged Withineach of said finger contacts between said contact engaging surfaces, anda ring shaped yoke arranged to extend Within said grooves of each ofsaid finger contacts for mounting said structure to an end of said stud.

14. A contact structure for a circuit breaker stud employing a pluralityof movable finger contacts mounted for independent limited movementaround said stud and a resilient housing for surrounding said contacts,said housing comprising a pair of spaced ringlike members interconnectedby -a plurality of pivotally mounted spaced members, said housingretaining said finger contacts in a given geometrical configuration andforming cooling surfaces for dissipating the heat of current conduction.

References Cited in the file of this patent UNITED STATES PATENTS2,300,893 Hayford Nov. 3, 1942 FOREIGN PATENTS 273,721 Italy Apr. 30,1930 392,880 Great Britain May 25, 1933 678,811 Germany July 22, 1939

